FIC03272 Datasheet, PDF (7/14 Pages) List of Unclassifed Manufacturers – Microprocessor for handling signals from the TGS4161 carbon dioxide sensor

TECHNICAL INFORMATION FOR FIC03272
4-10 Line test mode (Pin No. 4)
A line test mode can be activated by the input of an
“L” signal to port R70 at the moment of power supply.
Operation of the microprocessor and the surrounding
circuits will be tested according to the schedule
shown in Table 7. After powering on, signal outputs
change from Step 1 to Step 4 according to the table,
with Steps 1-3 lasting 5 seconds each. Afterwards,
Step 4 outputs will be maintained continuously until
the power is shut off.
Terminal
Signal Output
Name
Symbol
Pin No.
Step 1
Step 2
Step 3
CO2 concentration
signal
R91
25
Cd1 (ppm)
Note *1
Cd1 (ppm)
Cd1 (ppm)
Bias signal
Note *2
R90
24
0
255
128
Green LED
R63
19
L
H
(Note 3)
Red LED
R62
18
H
L
(Note 4)
Damper control
signal
R60
16
H
L
(Note 5)
Malfunction
R61
17
H
L
(Note 6)
Benchmark
renewal status
R92
26
H
L
H
Notes:
(1) Please refer to Sec. 4-1-4 - Input signal for damper control
(2) Please refer to Sec. 4-4 - Bias signal output
(3) H or L, as input to Pin #10 for initial warmup setting - refer to Sec. 4-1-1
(4) H or L, as input to Pin #11 for benchmark adjustment - refer to Sec. 4-1-2
(5) H or L, as input to Pin #12 for benchmark adjustment - refer to Sec. 4-1-2
(6) H or L, as input to Pin #13 for benchmark reset - refer to Sec. 4-1-3
(7) Outputs shown are held until power is shut off
Table 7 - Line test mode
Step 4
Cd1 (ppm)
128
H
H
H
H
H
5. Electrical Circuit for FIC03272
The following peripheral circuits are suggested when
using the FIC03272 with the TGS4161 sensor.
5-1 Circuit for driving sensor and for processing sensor signals
The block/circuit diagrams for driving the sensor and
processing its signals are shown in Figure 3 (below)
and Figure 4 (Page 8) respectively. Please note the
following items:
a) +5.0V should be applied to Pin No. 6 for the heater
of TGS4161.
b) +3.8V is the specified voltage to sensor pin No. 5
for the built-in thermistor which is connected in
series with an 8.2kΩ resistor. Output voltage across
the 8.2kΩ resistor is designed to be input to port
FIC03272
+3.8V
+5V
Thermistor
signal (VT)
Heater
voltage
(VH)
Sensor
voltage
(EMF)
4.5 times
Buffer _{+ amplification}
circuit
circuit
10 times _Regulation
amplification + _circuit
circuit
Bias signal (PWM signal)
Convert to DC
Buffer
circuit
Figure 3 - Block diagram for driving sensor and processing sensor signal
Revised 06/04
7